Radar system, radar control method, and program

Abstract

To provide a radar device, a radar control method, and a program with which it is possible to detect, with good accuracy, reverse running on a road the travel direction of which is defined.SOLUTION: There is provided, a radar device 2 that includes a transmit antenna 8 that transmits electromagnetic waves and a receive antenna 9 that receives the electromagnetic wave transmitted by the transmit antenna 8 and having been reflected. The radar device 2 comprises: a detection processing unit 21 that detects a target on the basis of the signal received by the receive antenna 9; a direction determination unit 22 that determines, on the basis of a direction in which a position of the target detected by the detection processing unit 21 moves, whether a direction of this movement is a forward run that goes along a predetermined direction or a reverse run that goes in a direction opposite to forward run; and a discrimination processing unit 23 that discriminates, on the basis of detection information of a forward-running vehicle 100 different from a reverse-running vehicle 101 (reverse-running target) having been determined as a reverse run by the direction determination unit 22, whether the reverse-running vehicle 101 is a real image or a virtual image.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a radar device, a radar control method, and a program for detecting reverse running of a moving object.

Background Art

[0002] Conventionally, a technique for detecting a moving object as a target using a radar has been known. For example, there is Patent Document 1 that describes this type of technique. Patent Document 1 relates to a radar device capable of distinguishing a virtual image from a real image even when multipath occurs.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, there are cases where a radar device detects a vehicle running in reverse on a highway or the like. In this case, if there is an obstacle such as a parked vehicle within the detection range of the radar, there is a risk that the electromagnetic wave is reflected by the obstacle and a virtual image (mirror image) of a vehicle running forward is erroneously detected as a vehicle running in reverse.

[0005] An object of the present invention is to provide a radar device, a radar control method, and a program capable of accurately detecting reverse running on a road where the traveling direction is defined.

Means for Solving the Problems

[0006] The present invention relates to a radar device comprising a transmitting antenna that transmits electromagnetic waves and a receiving antenna that receives reflections of electromagnetic waves transmitted by the transmitting antenna, the radar device comprising: a detection processing unit that detects a target based on a signal received by the receiving antenna; a direction determination unit that determines, based on the direction in which the position of the target detected by the detection processing unit moves, whether this direction of movement is forward movement along a predetermined direction or reverse movement in the opposite direction to the forward movement; and an identification processing unit that identifies whether the reverse-moving target is a real image or a virtual image based on detection information of a forward-moving target different from the reverse-moving target determined by the direction determination unit to be moving in the wrong direction.

[0007] If the transmitting antenna and the receiving antenna are installed facing the direction opposite to the reverse-moving object, and the identification processing unit obtains detection information indicating that a forward-moving object traveling in the correct direction has been newly detected within a predetermined distance from the position of the radar device within a predetermined time after the reverse-moving object is no longer detected, the reverse-moving object may be determined to be a virtual image.

[0008] The identification processing unit may determine that the forward-moving target is a virtual image if it has obtained detection information indicating that the forward-moving target is newly detected within the predetermined time and distance, and that the forward-moving target is located in a pre-set area.

[0009] The identification processing unit may determine that the reverse-moving target is a virtual image if it obtains detection information indicating that the forward-moving target has been newly detected within the predetermined time and distance, and that the direction of movement of the forward-moving target is in the opposite direction to the direction of movement of the reverse-moving target.

[0010] The identification processing unit may use as one of the conditions for determining that an object is a virtual image whether the absolute value of the velocity in the direction of movement of the reverse-moving object is equal to the absolute value of the velocity in the direction of movement of the forward-moving object.

[0011] The transmitting antenna and the receiving antenna are installed facing the forward-moving target, and the identification processing unit may determine the backward-moving target to be a virtual image if it obtains detection information indicating that a forward-moving target existed within a predetermined distance from the position of the radar device within a predetermined time until the backward-moving target was detected.

[0012] Furthermore, the present invention relates to a control method for a radar device comprising a transmitting antenna that transmits electromagnetic waves and a receiving antenna that receives reflections of electromagnetic waves transmitted by the transmitting antenna, the method comprising: a detection processing step of detecting a target based on a signal received by the receiving antenna; a direction determination step of determining whether the direction of movement of the target detected by the detection processing step is forward movement along a predetermined direction or reverse movement in the opposite direction to the forward movement; and an identification processing step of identifying whether the reverse-moving target is a real image or a virtual image based on detection information of a forward-moving target different from the reverse-moving target determined to be reverse-moving in the direction determination step.

[0013] Furthermore, the present invention relates to a computer for a radar device comprising a transmitting antenna that transmits electromagnetic waves and a receiving antenna that receives reflections of electromagnetic waves transmitted by the transmitting antenna, comprising: a detection processing function that detects a target based on a signal received by the receiving antenna; a direction determination function that determines, based on the direction in which the position of the target detected by the detection processing function moves, whether this direction of movement is forward movement along a predetermined direction or reverse movement in the opposite direction to the forward movement; and an identification processing function that identifies whether the reverse-moving target is a real image or a virtual image based on detection information of a forward-moving target different from the reverse-moving target determined by the direction determination function to be moving in the wrong direction. Regarding the program that executes this. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a radar device, a radar control method, and a program that can accurately detect wrong-way driving on roads where the direction of travel is predetermined. [Brief explanation of the drawing]

[0015] [Figure 1] It is a schematic diagram of a reverse running detection system including a radar device according to an embodiment of the present invention. [Figure 2] It is a diagram showing an example of the configuration of the antenna unit of the radar device in this embodiment. [Figure 3] It is a block diagram showing an example of the hardware configuration of the determination device of the radar device in this embodiment. [Figure 4] It is a block diagram showing an example of the functional configuration for performing reverse running detection of the determination device of the radar device in this embodiment. [Figure 5] It is a schematic plan view for explaining a case where a vehicle once determined to be running in reverse by a radar device installed to face the reverse running vehicle in this embodiment is determined to be a virtual image. [Figure 6] It is a graph showing the relationship between the distance and time of a forward running vehicle and its virtual image when the radar device is installed to face the reverse running vehicle. [Figure 7] It is a graph showing the relationship between the distance and time of a reverse running vehicle and its virtual image when the radar device is installed to face the reverse running vehicle. [Figure 8] It is a graph showing the relationship between coordinates and time for explaining that a newly detected forward running vehicle is located within a set area when a reverse running vehicle that is a virtual image is detected. [Figure 9] It is a graph showing the relationship between the speed and time of the moving directions of a forward running vehicle and its virtual image. [Figure 10] It is a graph showing the relationship between the speed and time of the moving directions of a reverse running vehicle and its virtual image. [Figure 11] It is a schematic plan view for explaining a case where a vehicle once determined to be running in reverse by a radar device installed to face the forward running vehicle in this embodiment is determined to be a virtual image. [Figure 12] It is a graph showing the relationship between the distance and time of a forward running vehicle and its virtual image when the radar device is installed to face the forward running vehicle. [Figure 13]A graph showing the relationship between the distance and time of a reverse-traveling vehicle and its virtual image when the radar device is installed facing the oncoming vehicle. [Figure 14] A flowchart showing an example of the reverse-travel detection process by the radar device of this embodiment.

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0017] FIG. 1 is a schematic diagram of a reverse-travel detection system 1 including a radar device 2 according to an embodiment of the present invention. As shown in FIG. 1, the reverse-travel detection system 1 of this embodiment includes a radar device 2, a display device 3, a staff computer 4, and a monitoring server 5.

[0018] <I The radar device 2 is a detection device for detecting a reverse-traveling vehicle 101 that travels in the opposite direction on a one-way road where the traveling direction is determined in advance. The radar device 2 is installed, for example, at the entrance and exit of an expressway interchange. The radar device 2 includes an antenna unit 6 that transmits electromagnetic waves and receives the reflected waves, and a determination device 10 that executes reverse-travel detection processing based on the reception signal of the antenna unit 6.

[0019] FIG. 2 is a diagram showing an example of the configuration of the antenna unit 6 of the radar device 2 of this embodiment. The antenna unit 6 in this example has at least one or more transmission antennas 8 and a plurality of reception antennas 9. Electromagnetic waves are irradiated from the transmission antenna 8 toward the road, and the scattered waves scattered by the vehicle are received by the plurality of reception antennas 9. The reception results of the plurality of reception antennas 9 are analyzed by the determination device 10 to determine whether there is a reverse-traveling vehicle 101 traveling in the opposite direction. The configuration for detecting reverse travel by this determination device I0 will be described later.

[0020] The display device 3 is a notification means that displays a message such as "No driving in the wrong direction" to the driver of the vehicle 101 driving in the wrong direction. The display device 3 in this embodiment is connected to the judgment device 10 of the radar device 2, and the display content can be changed based on the judgment result of the judgment device 10.

[0021] The radar device 2's detection device 10, the staff computer 4, and the monitoring server 5 are connected via a network 7. Network 7 is configured, for example, as an IP-VPN (Virtual Private Network). The monitoring server 5 performs processing such as notifying the staff computer 4 that wrong-way driving is occurring on the road where the radar device 2 is installed, based on the detection result of the radar device 2's detection device 10. For example, if the radar device 2 determines that a wrong-way driving vehicle 101 exists, the detection result is sent to the monitoring server 5, and the monitoring server 5 notifies staff that wrong-way driving is occurring by sending an email to a pre-registered staff computer 4.

[0022] The above describes the wrong-way driving detection system 1, but this configuration is merely an example and is not the only possible configuration. Next, we will describe the detailed configuration for detecting wrong-way driving using the radar device 2.

[0023] First, an example of the hardware configuration of the determination device 10 will be described with reference to Figure 3. Figure 3 is a block diagram showing an example of the hardware configuration of the determination device 10 of the radar device 2 in this embodiment.

[0024] As shown in Figure 3, the determination device 10 is a computer equipped with a processor 11, ROM (read-only memory) 12, RAM (random-access memory) 13, auxiliary storage device 14, and communication I / F (interface) 15, with each part connected by a bus or the like.

[0025] The processor 11 is the central part of the computer that performs calculations and control necessary for the operation of the determination device 10, and performs various calculations and processes. The processor 11 is, for example, a CPU (central processing unit), MPU (micro processing unit), SoC (system on a chip), DSP (digital signal processor), GPU (graphics processing unit), ASIC (application specific integrated circuit), PLD (programmable logic device), or FPGA (field-programmable gate array). Alternatively, the processor 11 is a combination of several of these. Furthermore, the processor 11 may also be a combination of these with hardware accelerators, etc.

[0026] The processor 11 controls various parts of the determination device 10 to realize various functions based on programs such as firmware, system software, and application software stored in the ROM 12 or auxiliary storage device 14. The processor 11 also executes the processes described later based on the said programs. Note that some or all of the said programs may be incorporated into the circuit of the processor 11.

[0027] ROM12 and RAM13 are the main memory of the computer, with the processor 11 at its core. ROM12 is a non-volatile memory used exclusively for reading data. ROM12 stores programs such as firmware. ROM12 also stores data used by the processor 11 in various processes. RAM13 is memory used for reading and writing data. RAM13 is used as a work area to store data temporarily used by the processor 11 in various processes. RAM13 is typically a volatile memory.

[0028] The auxiliary storage device 14 is, for example, an EEPROM (electric erasable programmable read-only memory), an HDD (hard disk drive), or flash memory. The auxiliary storage device 14 stores, for example, system software and application software from the above-mentioned programs. The auxiliary storage device 14 also stores data used by the processor 11 in performing various processes, data generated by processing by the processor 11, and various setting values.

[0029] The communication interface 15 is an interface for communicating with external devices such as the display device 3 and the monitoring server 5. The determination result of the determination device 10 is transmitted from the communication interface 15 to the monitoring server 5 via the network 7.

[0030] Next, the functions of the determination device 10 implemented by the processor 11 will be described. Figure 4 is a block diagram showing an example of the functional configuration of the determination device 10 for detecting wrong-way driving in the radar device 2 of this embodiment. As shown in Figure 4, the determination device 10 includes a communication processing unit 20, a detection processing unit 21, a direction determination unit 22, and an identification processing unit 23 as functional units executed by the processor 11.

[0031] The communication processing unit 20 executes processing for communication with external devices via the communication interface 15. If reverse driving is detected, the communication processing unit 20 sends a message to the monitoring server 5 indicating that reverse driving has occurred. Display information for the display device 3 is also sent by the communication processing unit 20 via the communication interface 15.

[0032] The detection processing unit 21 performs a process to detect targets based on signals received by the multiple receiving antennas 9 of the antenna unit 6. This allows moving objects such as vehicles within the detection range of the radar device 2 to be detected as targets. The detection processing unit 21 also acquires information about the targets (position, speed, and azimuth angle, etc.).

[0033] The direction determination unit 22 performs a process to determine the direction in which the object detected by the detection processing unit 21 is moving (hereinafter referred to as the travel direction). Roads onto which the radar device 2 emits electromagnetic waves have predetermined travel directions, such as one-way streets. The direction determination unit 22 determines, based on pre-set conditions, whether the object's travel direction is forward-moving, following the designated travel direction on the road, or reverse-moving, in the opposite direction to the designated direction on the road. For example, the direction determination unit 22 makes this determination based on the travel direction component of the object's movement direction detected by the detection processing unit 21. For convenience, in the following explanation, an object determined by the direction determination unit 22 to be moving forward-moving will be referred to as a forward-moving vehicle 100, and an object determined to be moving in the wrong direction will be referred to as a reverse-moving vehicle 101.

[0034] The identification processing unit 23 acquires detection information about the target acquired by the detection processing unit 21 and the direction determination unit 22, and performs an identification process based on predetermined conditions to determine whether the vehicle 101 traveling in the wrong direction, as determined by the direction determination unit 22, is a real image or a virtual image. The detection information includes the actual direction of movement of the vehicle traveling in the correct direction 100 and the vehicle traveling in the wrong direction 101, the speed, the direction of travel indicating whether it is traveling in the correct direction or the wrong direction, the detection time, the time it disappeared, etc.

[0035] If the identification processing unit 23 determines that the vehicle 101 traveling in the wrong direction, as determined by the direction determination unit 22, is a real image, then it means that the vehicle 101 actually exists. Conversely, if the identification processing unit 23 determines that the vehicle 101 traveling in the wrong direction, as determined by the direction determination unit 22, is a virtual image, then it means that a virtual image (mirror image) caused by an obstacle such as a parked vehicle was determined to be the vehicle traveling in the wrong direction, and therefore, the vehicle is not actually traveling in the wrong direction.

[0036] Next, the identification process by the identification processing unit 23 will be described. Figure 5 is a schematic plan view illustrating the case in which a vehicle 101 traveling in the wrong direction, which was initially determined to be traveling in the wrong direction by the radar device 2 of this embodiment, is determined to be a virtual image.

[0037] In Figure 5, the radar device 2 is installed so as to face the vehicle 101 traveling in the wrong direction, which is the opposite direction to the one-way road 150 where the forward direction of travel is set. In other words, the radio wave transmitting and receiving surface of the radar device 2 is facing the direction from which the vehicle 101 is traveling. In addition, a relatively large parked vehicle 110, such as a truck, is located near the installation location of the radar device 2.

[0038] When a vehicle 100 traveling in the correct direction on a one-way road 150 enters the detection range of the radar device 2, electromagnetic waves emitted from the radar device 2 are reflected by a parked vehicle 110, and these reflected waves reach the vehicle 100 and are reflected again. A portion of these reflected waves is reflected back by the parked vehicle 110 and received by the antenna unit 6 of the radar device 2. As a result, a virtual image of a vehicle traveling in the wrong direction 101, which does not actually exist on the straight line in the direction of incidence of these re-reflected waves, is detected. In order to improve the accuracy of wrong-way vehicle detection, it is necessary to distinguish whether the wrong-way vehicle 101 is a real image or a virtual image.

[0039] Here, with reference to Figures 6 and 7, the relationship between a vehicle traveling in the correct direction 100 and its virtual image (sometimes referred to as a ghost), and the relationship between a vehicle traveling in the wrong direction 101 and its virtual image (ghost) will be explained. Figure 6 is a graph showing the relationship between a vehicle traveling in the correct direction 100 and its virtual image when the radar device 2 is installed facing the vehicle traveling in the wrong direction 101. Figure 7 is a graph showing the relationship between the vehicle traveling in the wrong direction 101 and its virtual image when the radar device 2 is installed facing the vehicle traveling in the wrong direction 101. In both Figures 6 and 7, the horizontal axis represents the passage of time, and the vertical axis represents the distance from the radar device 2 to the detected vehicle. Furthermore, in the following explanation, for the sake of clarity, it is written as if the detected image is identified as either a real image or a virtual image, but in actual processing, virtual images are also detected as real images, and post-detection processing determines whether the image of the initially detected vehicle traveling in the wrong direction 101 is a virtual image or not.

[0040] As shown in Figure 6, when a vehicle traveling in the wrong direction (vehicle 101) is detected as a ghost of a vehicle traveling in the correct direction (vehicle 100), the radar device 2 detects the virtual image of the vehicle traveling in the wrong direction (vehicle 101) before the real vehicle traveling in the correct direction (vehicle 100). This vehicle traveling in the wrong direction (vehicle 101) shows behavior in which its distance from the radar device 2 decreases over time. At this point, it is not possible to distinguish whether the detected vehicle traveling in the wrong direction (vehicle 101) is a real vehicle or a ghost. The vehicle traveling in the wrong direction (vehicle 101) disappears once it has approached the radar device 2 to a certain extent, and the real vehicle traveling in the correct direction (vehicle 100) is detected in its place. The vehicle traveling in the correct direction (vehicle 100) is located near the radar device 2 at the start of detection by the radar device 2, and shows behavior in which its distance from the radar device 2 increases over time.

[0041] As shown in Figure 7, when the vehicle traveling in the correct direction 100 is detected as a ghost of the vehicle traveling in the wrong direction 101, the actual vehicle traveling in the wrong direction 101 is detected first by the radar device 2. As time passes, the distance between the vehicle traveling in the wrong direction 101 and the radar device 2 decreases, and it disappears once it has gotten close enough. In its place, the ghost vehicle traveling in the correct direction 100 is detected. At this point, it is not possible to distinguish whether the detected vehicle traveling in the wrong direction 101 is a real vehicle or a ghost. The difference from the case in Figure 6 is that the distance between the ghost vehicle traveling in the correct direction 100 and the radar device 2 at the start of detection is greater than that of the real vehicle traveling in the wrong direction 101. In other words, if the vehicle traveling in the wrong direction 101 is a real vehicle, the distance between the ghost vehicle traveling in the correct direction 100 and the radar device 2 at the start of detection will increase. Thus, it can be confirmed that the behavior of the forward-moving vehicle 100 detected after the disappearance of the wrong-way vehicle 101 differs depending on whether the wrong-way vehicle 101 shown in Figure 6 is a ghost or a real vehicle shown in Figure 7.

[0042] Therefore, in this embodiment, a predetermined condition for the identification process is whether or not a vehicle traveling in the correct direction 100 is detected within a certain time and distance range after the vehicle traveling in the wrong direction 101 has disappeared. Based on this predetermined condition, it is determined whether the detected vehicle traveling in the wrong direction 101 is a real image or a virtual image. If a vehicle traveling in the correct direction 100 is detected within a certain time and distance range after the vehicle traveling in the wrong direction 101 has disappeared, the state is as shown in Figure 6, and the detected vehicle traveling in the wrong direction 101 is identified as a virtual image. Conversely, if a vehicle traveling in the correct direction 100 detected within a certain time after the vehicle traveling in the wrong direction 101 has disappeared is outside the certain distance range, the state is as shown in Figure 7, and the detected vehicle traveling in the wrong direction 101 is identified as a real image. This makes it possible to achieve highly accurate wrong-way detection without misidentifying a virtual image as the occurrence of wrong-way driving.

[0043] Next, we will describe an example in which further conditions are added to the predetermined conditions of the identification process described above. In the following description, configurations that are common or similar to those already described will be denoted by the same reference numerals, and detailed explanations will be omitted.

[0044] Figure 8 is a graph illustrating that when a virtual image of a vehicle traveling in the wrong direction (vehicle 101) is detected, a newly detected vehicle traveling in the correct direction (vehicle 100) is located within the set area. The vertical axis of Figure 8 is the figure. 5 The xy coordinates shown represent the value of the y-coordinate defined by the xy coordinate system, with the horizontal axis indicating the passage of time. The xy coordinate system is a coordinate system in a plan view, where the y-axis is the direction tilted 45 degrees to the direction perpendicular to the forward direction, and the x-axis is the direction perpendicular to this y-axis.

[0045] In this example, the identification processing unit 23 sets a predetermined range of y coordinates as a setting area. The rectangle shown in Figure 8 is determined based on a predetermined time and the set range of y coordinates, and the condition for determining that the initially detected wrong-way vehicle 101 is a phantom image is when a forward-moving vehicle 100 is detected inside this rectangle after the detection of the wrong-way vehicle 101. In other words, the three predetermined conditions for the identification process are: it is within a predetermined time after the disappearance of the wrong-way vehicle 101, the detected forward-moving vehicle 100 is within a predetermined distance, and the detected forward-moving vehicle 100 is included in the setting area. When these three conditions are met, it is determined that the wrong-way vehicle 101 detected once is a phantom image and that no wrong-way driving actually occurred.

[0046] Next, referring to Figures 9 and 10, we will describe an example of adding conditions different from those described with reference to Figure 8 to the predetermined conditions of the identification process. Figure 9 is a graph showing the relationship between the speed and time in the respective directions of movement of a forward-moving vehicle 100 and its virtual image, and Figure 10 is a graph showing the relationship between the speed and time in the direction of movement when a reverse-moving vehicle 101 is continuously detected. In both Figures 9 and 10, the vertical axis represents the speed of the vehicle, and the horizontal axis represents the passage of time. When a reverse-moving vehicle 101 is continuously detected without a virtual image, evaluation based solely on distance would result in a situation like that between Figures 6 and 7, and there is a possibility of misidentifying it as a virtual image.

[0047] Figures 9 and 10 plot the vehicle's motion components separated into x-direction and y-direction components. As shown inside the rectangle in Figure 9, the x-direction velocity of the virtual image of the forward-moving vehicle 100 is around -10 m / s to -12.5 m / s, and the y-direction velocity is around 8 m / s to 11 m / s. In contrast, the x-direction velocity of the real image of the forward-moving vehicle 100 is around 10 m / s to 14 m / s, and the y-direction velocity is around -6 m / s to -10 m / s. That is, the sign of the velocity in the direction of movement of the reverse-moving vehicle 101 is opposite to the sign of the velocity in the direction of movement of the forward-moving vehicle 100. On the other hand, in Figure 10, the relationship in which the sign of the velocity of the reverse-moving vehicle 101 is opposite does not hold.

[0048] Therefore, by adding the condition that the sign of the speed in the direction of movement of the wrong-way vehicle 101 and the sign of the speed in the direction of movement of the forward-moving vehicle 100 are opposite, as shown in Figure 9, the accuracy of the determination can be further improved. Specifically, the three conditions for the identification process are: that it is within a predetermined time after the disappearance of the wrong-way vehicle 101; that the detected forward-moving vehicle 100 is within a predetermined distance; and that the direction of movement of the wrong-way vehicle 101 and the forward-moving vehicle 100 are opposite. If these three conditions are met, the wrong-way vehicle 101 that was detected is a phantom image, and it is determined that no wrong-way driving actually occurred.

[0049] Furthermore, the absolute value of the velocity in the direction of movement can also be added as a predetermined condition for the identification process. It is necessary to distinguish between the event in which two separate vehicles, the forward-moving vehicle 100 and the reverse-moving vehicle 101, exist, and the event in which a single vehicle produces both a real image and a virtual image. Figure 9 also plots the absolute values ​​of the velocity in the direction of movement of the reverse-moving vehicle 101 and the forward-moving vehicle 100. Inside the rectangle in Figure 9, the absolute values ​​of the velocity in the direction of movement of the reverse-moving vehicle 101 and the forward-moving vehicle 100 are approximately the same. This suggests that both the virtual and real images originate from the same vehicle. On the other hand, if the forward-moving vehicle 100 and the reverse-moving vehicle 101 each exist as separate real images, the probability of their absolute values ​​being approximately the same is low. Therefore, determining that the absolute value of the velocity in the direction of movement of the reverse-moving vehicle 101 and the absolute value of the velocity in the direction of movement of the forward-moving vehicle 100 are equal can also be one of the conditions for the identification process. In this context, "determined to be equal in absolute value" includes not only cases where they are exactly the same, but also cases where they are approximately the same with a certain degree of leeway. This condition is a fourth condition, in addition to the aforementioned condition that the direction of movement of the wrong-way vehicle 101 and the direction of movement of the forward-moving vehicle 100 are opposite. In some cases, this may be a fourth condition, in addition to the aforementioned condition that the detected forward-moving vehicle 100 is included in the set area, or it may be a third condition, replacing the aforementioned condition that the direction of movement of the wrong-way vehicle 101 and the direction of movement of the forward-moving vehicle 100 are opposite.

[0050] The above describes a configuration in which the radar device 2 is installed facing the vehicle 101 traveling in the wrong direction, but this configuration is not the only one. The orientation of the radar device 2 may change depending on the position of the reflective objects that reflect electromagnetic waves and other layout constraints.

[0051] Next, we will describe a configuration in which the radar device 2 is installed facing the direction of the vehicle 100 traveling in the correct direction. Figure 11 is a schematic plan view illustrating a case in which a vehicle initially determined to be traveling in the wrong direction by the radar device 2 installed facing the vehicle 100 traveling in the correct direction is determined to be a false image. In Figure 11, the radar device 2 is installed facing the vehicle 100 traveling in the correct direction, which is moving along a one-way road 151 where the direction of travel is set. In other words, the radio wave transmitting and receiving surface of the radar device 2 faces the direction from which the vehicle 100 is traveling. In addition, a relatively large parked vehicle 110, such as a truck, is located near the installation location of the radar device 2.

[0052] In the case shown in Figure 11, electromagnetic waves emitted from the radar device 2 are reflected by the parked vehicle 110, and these reflected waves reach the vehicle 100 traveling in the correct direction on the one-way road 151, where they are reflected again. A portion of these reflected waves is re-reflected by the parked vehicle 110, resulting in the detection of a virtual image of a vehicle traveling in the wrong direction 101, which does not actually exist on the straight line in the direction of incidence of these re-reflected waves. To improve the accuracy of wrong-way vehicle detection, it is necessary to distinguish whether the wrong-way vehicle 101 is a real image or a virtual image.

[0053] Figure 12 is a graph showing the relationship between the distance and time between a vehicle traveling in the correct direction 100 and its virtual image when the radar device 2 is installed facing the vehicle traveling in the correct direction 100. Figure 13 is a graph showing the relationship between the distance and time between a vehicle traveling in the wrong direction 101 and its virtual image when the radar device 2 is installed facing the vehicle traveling in the correct direction 100. In the following explanation, for the sake of clarity, it is written as if the detected image is identified as either a real image or a virtual image. However, in actual processing, virtual images are also detected as real images, and post-detection processing determines whether the detected image of the vehicle traveling in the wrong direction 101 is a virtual image or not.

[0054] As shown in Figure 12, when a vehicle traveling in the wrong direction 101 is detected as a ghost image of a vehicle traveling in the correct direction 100, the actual vehicle traveling in the correct direction 100 is detected first by the radar device 2. As time passes, the distance between the vehicle traveling in the correct direction 100 and the radar device 2 decreases, and it disappears once it has gotten close enough. In its place, the ghost image of the vehicle traveling in the wrong direction 101 is detected.

[0055] As shown in Figure 13, when the forward-moving vehicle 100 is detected as a ghost of the wrong-way moving vehicle 101, the virtual image of the forward-moving vehicle 100 is detected by the radar device 2 before the real image of the wrong-way moving vehicle 101. This forward-moving vehicle 100 disappears after approaching the radar device 2 to a certain extent, and the real image of the wrong-way moving vehicle 101 is detected instead. The distance between the ghost forward-moving vehicle 100 detected before the wrong-way moving vehicle 101 is detected and the radar device 2 is further away than the real forward-moving vehicle 100, which is the difference from Figure 12. In other words, when the wrong-way moving vehicle 101 is a real vehicle, the distance between the ghost forward-moving vehicle 100 and the radar device 2 will be greater. Thus, it can be confirmed that the behavior of the forward-moving vehicle 100 detected before the wrong-way moving vehicle 101 differs between the case where the wrong-way moving vehicle 101 is a ghost as shown in Figure 12 and the case where the wrong-way moving vehicle 101 is a real vehicle as shown in Figure 13.

[0056] As shown in Figures 12 and 13, when the radar device 2 is installed facing a vehicle traveling in the correct direction 100, in order to distinguish whether a target that has been determined to be a vehicle traveling in the wrong direction 101 is a real image or a virtual image, the condition for the identification process is that a vehicle traveling in the correct direction 100 is detected within a certain distance range within a certain time period before the appearance of the vehicle traveling in the wrong direction 101. Even if a vehicle is determined to be a vehicle traveling in the wrong direction 101, if a vehicle traveling in the correct direction 100 was detected within a certain distance range within a certain time period before the appearance of the vehicle traveling in the wrong direction 101, it is possible to identify that the vehicle traveling in the wrong direction 101 is a virtual image.

[0057] The predetermined conditions for multiple types of identification processing have been described above. Next, with reference to Figure 14, the overall flow of the wrong-way driving detection process by the radar device 2 of this embodiment will be described. Figure 14 is a flowchart showing an example of the flow of the wrong-way driving detection process by the radar device 2 of this embodiment.

[0058] When the flow shown in Figure 14 begins, the detection processing unit 21 first performs the process of detecting an object based on signals from multiple receiving antennas 9 (step S101). At this point, a moving object such as a vehicle is detected as an object.

[0059] Next, the direction determination unit 22 starts the process of determining whether the detected target is traveling in the forward or reverse direction (step S102). The direction determination unit 22 determines whether the target is a vehicle traveling in the forward direction 100 or a vehicle traveling in the reverse direction 101, for example, based on the component of the target's direction of movement. If a vehicle traveling in the reverse direction 101 is not detected, the direction determination unit 22 skips the subsequent processing and terminates the process (step S103; No). If a vehicle traveling in the reverse direction 101 is detected, the direction determination unit 22 proceeds to step S104 (step S103; Yes).

[0060] In step S104, the communication processing unit 20 performs a primary action to display or emphasize the "no wrong-way driving" rule on the display device 3 based on the fact that a wrong-way driving determination has been made once (step S104). At this point, the wrong-way driving vehicle 101 may be a virtual image, but since the display device 3 is installed facing the wrong-way driving vehicle 101, the impact on the forward-moving vehicle 100 is minimal. The display resulting from the primary action ends, for example, after a predetermined time has elapsed or after the wrong-way driving vehicle 101 disappears from the radar device 2.

[0061] After the processing in step S104, the identification processing unit 23 starts a determination process to determine whether or not there is a forward-moving vehicle 100 that satisfies predetermined conditions for the identification process (step S105). The predetermined conditions for the identification process are, for example, any of the predetermined conditions for the identification process described above that are selected in advance. If the identification processing unit 23 detects a forward-moving vehicle 100 that satisfies the predetermined conditions for the identification process, it determines that the reverse-moving vehicle 101 is a virtual image, and therefore skips the subsequent processing and terminates the process for the time being (step S106; Yes).

[0062] If no forward-moving vehicle 100 is detected, the identification processing unit 23 proceeds to step S107 (step S106; No). In step S107, the identification processing unit 23 confirms that the reverse-moving vehicle 101 determined by the direction determination unit 22 is a real image and proceeds to the communication processing unit 20 (step S107). Next, the communication processing unit 20 transmits to the external monitoring server 5 that a reverse-moving vehicle 101 has occurred, along with the location information and time information of the radar device 2 (step S108).

[0063] As described above, the radar device 2 of this embodiment is a radar device 2 that includes a receiving antenna 9 that receives reflections of electromagnetic waves transmitted by a transmitting antenna 8 that transmits electromagnetic waves, and includes a detection processing unit 21 that detects a target based on the signal received by the receiving antenna 9, a direction determination unit 22 that determines whether the direction of movement of the target detected by the detection processing unit 21 is forward movement along a predetermined direction or reverse movement, and an identification processing unit 23 that identifies whether the reverse-moving vehicle 101 is a real image or a virtual image based on detection information of a forward-moving vehicle (forward-moving target) 100 that is different from the reverse-moving vehicle (reverse-moving target) 101 that the direction determination unit 22 has determined to be moving in the reverse direction.

[0064] This makes it possible to distinguish whether the detected wrong-way vehicle 101 is a virtual image (mirror image) caused by a parked vehicle 110 or the like, and to accurately detect whether or not a wrong-way vehicle 101 actually occurred.

[0065] Furthermore, if the transmitting antenna 8 and the receiving antenna 9 are installed facing the direction opposite to the wrong-way vehicle 101, the identification processing unit 23 can determine that the wrong-way vehicle 101 is a false image if it obtains detection information indicating that a forward-moving vehicle 100 traveling in the correct direction within a predetermined distance from the position of the radar device 2 has been newly detected within a predetermined time after the wrong-way vehicle 101 is no longer detected.

[0066] As a result, the radar device 2 can accurately distinguish between the real and virtual images of the vehicle traveling in the wrong direction by utilizing the positional relationship in which the transmitting antenna 8 and receiving antenna 9 are positioned facing the vehicle traveling in the wrong direction 101, and the distance between the radar device 2 and the virtual image of the vehicle traveling in the wrong direction 101 and the real image of the vehicle traveling in the correct direction 100.

[0067] Furthermore, the identification processing unit 23 can also determine that the wrong-way vehicle 101 is a false image if it obtains detection information indicating that a forward-moving vehicle 100 is newly detected within a predetermined time and within a predetermined distance from the radar device 2 after the wrong-way vehicle 101 is no longer detected, and that the forward-moving vehicle 100 is located in a pre-set area.

[0068] This adds the condition that the vehicle must be present in the designated area, allowing for more accurate identification of the real and virtual images of the vehicle 101 traveling in the wrong direction by utilizing its positional relationship with the radar device 2.

[0069] The identification processing unit 23 determines that the wrong-way vehicle 101 is a false image when it obtains detection information indicating that a forward-moving vehicle 100 is newly detected within a predetermined time and within a predetermined distance from the radar device 2 after the wrong-way vehicle 101 is no longer detected, and furthermore, the direction of movement of the forward-moving vehicle 100 is in the opposite direction to the direction of movement of the wrong-way vehicle 101.

[0070] This allows for accurate identification of the real and virtual images of the reverse-moving vehicle 101 by utilizing the fact that the direction of movement of the virtual image of the reverse-moving vehicle 101 is opposite to the direction of movement of the real image of the forward-moving vehicle 100.

[0071] Furthermore, the identification processing unit 23 may also use the determination that the absolute value of the speed of the vehicle moving in the wrong direction 101 is equal to the absolute value of the speed of the vehicle moving in the right direction 100 as one of the conditions for determining that it is a virtual image.

[0072] This allows for further improvement of the accuracy of the identification process by utilizing the fact that the absolute value of the movement speed of the real forward-moving vehicle 100 and the absolute value of the movement speed of the virtual reverse-moving vehicle 101 are approximately the same.

[0073] Furthermore, if the transmitting antenna 8 and the receiving antenna 9 are installed facing the vehicle 100 traveling in the correct direction, the identification processing unit 23 will determine the vehicle 101 traveling in the wrong direction to be a false image if it obtains detection information indicating that a vehicle 100 traveling in the correct direction was located within a predetermined distance from the position of the radar device 2 within a predetermined time until the vehicle 101 traveling in the wrong direction is detected.

[0074] This allows for accurate identification of the real and virtual images of the vehicle traveling in the wrong direction by utilizing the relative positions of the transmitting antenna 8 and the receiving antenna 9, which are positioned facing the vehicle traveling in the correct direction 100, and the distance between the radar device 2 of the vehicle traveling in the wrong direction 101 (which is a virtual image) and the vehicle traveling in the correct direction 100 (which is a real image).

[0075] Furthermore, the control method for the radar device of this embodiment includes: a detection processing step of detecting a target based on a signal received by the receiving antenna 9; a direction determination step of determining whether the direction of movement of the target detected in the detection processing step is forward movement along a predetermined direction or reverse movement in the opposite direction of forward movement; and an identification processing step of determining whether the reverse-moving vehicle 101 is a real image or a virtual image based on detection information of a forward-moving vehicle 100 that is different from the reverse-moving vehicle 101 determined to be reverse-moving in the direction determination step.

[0076] This makes it possible to distinguish whether the detected wrong-way vehicle 101 is a virtual image (mirror image) caused by a parked vehicle 110 or the like, and to accurately detect whether or not a wrong-way vehicle 101 actually occurred.

[0077] Furthermore, the program of this embodiment causes the determination device 10, which is the computer of the radar device 2, to execute a detection processing function that detects a target based on the signal received by the receiving antenna 9; a direction determination function that determines whether the direction of movement of the target detected by the detection processing function is forward movement along a predetermined direction or reverse movement; and an identification processing function that identifies whether the reverse-moving vehicle 101 is a real image or a virtual image based on detection information of a forward-moving vehicle 100 that is different from the reverse-moving vehicle 101 that the direction determination function has determined to be moving in the wrong direction.

[0078] This makes it possible to distinguish whether the detected wrong-way vehicle 101 is a virtual image (mirror image) caused by a parked vehicle 110 or the like, and to accurately detect whether or not a wrong-way vehicle 101 actually occurred.

[0079] Although embodiments and variations of the present invention have been described above, the present invention is not limited to the embodiments described above and can be modified as appropriate.

[0080] Furthermore, the series of processes in the above-described embodiments and modifications can be executed by hardware or by software. When the series of processes are executed by software, the programs constituting the software are installed on a computer or the like from a network or recording medium. The computer may be a computer built into dedicated hardware. Alternatively, the computer may be a computer capable of performing various functions by installing various programs, such as a general-purpose personal computer. [Explanation of symbols]

[0081] 1. Wrong-way driving detection system 2. Radar equipment 21 Detection Processing Unit 22 Direction determination unit 23 Identification Processing Unit 100 Vehicles traveling in the correct direction (vehicles traveling in the correct direction) 101 Vehicle driving in the wrong direction (Vehicle driving in the wrong direction marker)

Claims

1. A radar device comprising a transmitting antenna that transmits electromagnetic waves and a receiving antenna that receives reflections of electromagnetic waves transmitted by the transmitting antenna, A detection processing unit that detects a target based on the signal received by the receiving antenna, A direction determination unit determines, based on the direction in which the position of the target detected by the detection processing unit moves, whether this direction of movement is forward movement along a predetermined direction or reverse movement in the opposite direction to the forward movement. An identification processing unit identifies whether a reverse-moving target is a real image or a virtual image based on detection information of a forward-moving target that is different from the reverse-moving target that the direction determination unit has determined to be reverse-moving, Equipped with, The transmitting antenna and the receiving antenna are installed facing the direction opposite to the object traveling in the wrong direction. The aforementioned identification processing unit, A radar device that determines the forward-moving object to be a virtual image if it obtains detection information indicating that a forward-moving object has been newly detected within a predetermined distance from the position of the radar device within a predetermined time after the forward-moving object is no longer detected.

2. The aforementioned identification processing unit, The radar device according to claim 1, which determines that the forward-moving target is a virtual image when the forward-moving target is newly detected within the predetermined time and distance, and when the detection information indicating that the forward-moving target is located in a pre-set area is acquired.

3. The aforementioned identification processing unit, The radar device according to claim 1, which determines that the forward-moving target is a virtual image when it obtains detection information indicating that the forward-moving target is newly detected within the predetermined time and distance, and further indicates that the direction of movement of the forward-moving target is in the opposite direction to the direction of movement of the reverse-moving target.

4. The aforementioned identification processing unit, The radar device according to any one of claims 1 to 3, wherein one of the conditions for determining that an object is a virtual image is that the absolute value of the velocity in the direction of movement of the object moving in the reverse direction is equal to the absolute value of the velocity in the direction of movement of the object moving in the forward direction.

5. A radar device comprising a transmitting antenna that transmits electromagnetic waves and a receiving antenna that receives reflections of electromagnetic waves transmitted by the transmitting antenna, A detection processing unit that detects a target based on the signal received by the receiving antenna, A direction determination unit determines, based on the direction in which the position of the target detected by the detection processing unit moves, whether this direction of movement is forward movement along a predetermined direction or reverse movement in the opposite direction to the forward movement. An identification processing unit identifies whether a reverse-moving target is a real image or a virtual image based on detection information of a forward-moving target that is different from the reverse-moving target that the direction determination unit has determined to be reverse-moving, The transmitting antenna and the receiving antenna are installed facing the direction opposite to the forward-moving target. The aforementioned identification processing unit, A radar device that determines the forward-moving object to be a virtual image if it obtains detection information indicating that a forward-moving object existed within a predetermined distance from the position of the radar device within a predetermined time period until the forward-moving object was detected.

6. A control method for a radar system comprising a transmitting antenna that transmits electromagnetic waves and a receiving antenna that receives reflections of electromagnetic waves transmitted by the transmitting antenna, A detection process step in which the receiving antenna detects a target based on the signal it receives, A direction determination step is performed to determine whether the direction of movement of the object detected in the detection processing step is forward movement along a predetermined direction or reverse movement in the opposite direction to the forward movement, The process includes an identification step that identifies whether the reverse-moving target is a real image or a virtual image based on detection information of a forward-moving target different from the reverse-moving target determined to be reverse-moving in the direction determination step, The transmitting antenna and the receiving antenna are installed facing the direction opposite to the object traveling in the wrong direction. In the aforementioned identification process step, A control method for a radar device in which, if detection information is obtained indicating that a forward-moving object has been newly detected within a predetermined distance from the position of the radar device within a predetermined time after the forward-moving object is no longer detected, the radar device determines that the forward-moving object is a virtual image.

7. A control method for a radar device comprising a transmitting antenna that transmits electromagnetic waves and a receiving antenna that receives reflections of electromagnetic waves transmitted by the transmitting antenna, A detection process step in which the receiving antenna detects a target based on the signal it receives, A direction determination step is performed to determine whether the direction of movement of the object detected in the detection processing step is forward movement along a predetermined direction or reverse movement in the opposite direction to the forward movement, The process includes an identification step that identifies whether the reverse-moving target is a real image or a virtual image based on detection information of a forward-moving target different from the reverse-moving target determined to be reverse-moving in the direction determination step, The transmitting antenna and the receiving antenna are installed facing the direction opposite to the forward-moving target. In the aforementioned identification process step, A control method for a radar device that determines the forward-moving object to be a virtual image if it obtains detection information indicating that a forward-moving object existed within a predetermined distance from the position of the radar device within a predetermined time period until the forward-moving object was detected.

8. A computer in a radar system that includes a transmitting antenna for transmitting electromagnetic waves and a receiving antenna for receiving reflections of electromagnetic waves transmitted by the transmitting antenna, The receiving antenna has a detection processing function that detects a target based on the signal it receives, A direction determination function determines whether the direction of movement of the target detected by the detection processing function is forward movement along a predetermined direction or reverse movement in the opposite direction of the forward movement, The direction determination function then executes an identification processing function that identifies whether the reverse-moving target is a real image or a virtual image based on detection information of a forward-moving target that is different from the reverse-moving target that the direction determination function has determined to be reverse-moving. The transmitting antenna and the receiving antenna are installed facing the direction opposite to the object traveling in the wrong direction. The aforementioned identification processing function is, A program that determines the aforementioned wrong-way moving object to be a virtual image if, within a predetermined time after the aforementioned wrong-way moving object is no longer detected, detection information is obtained indicating that a forward-moving object traveling in the correct direction has been newly detected within a predetermined distance from the position of the radar device.

9. A computer for a radar device comprising a transmitting antenna that transmits electromagnetic waves and a receiving antenna that receives reflections of electromagnetic waves transmitted by the transmitting antenna, The receiving antenna has a detection processing function that detects a target based on the signal it receives, A direction determination function determines whether the direction of movement of the target detected by the detection processing function is forward movement along a predetermined direction or reverse movement in the opposite direction of the forward movement, The direction determination function then executes an identification processing function that identifies whether the reverse-moving target is a real image or a virtual image based on detection information of a forward-moving target that is different from the reverse-moving target that the direction determination function has determined to be reverse-moving. The transmitting antenna and the receiving antenna are installed facing the direction opposite to the forward-moving target. The aforementioned identification processing function is, A program that determines the reverse-moving object to be a virtual image if it obtains detection information indicating that a forward-moving object existed within a predetermined distance from the position of the radar device within a predetermined time period before the reverse-moving object was detected.

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